Overview of changes for 1.2
==============================
• Add simple wrapper functions for JsonGenerator and JsonParser to
  write and read a string from and to a JsonNode, respectively
• Drop use of deprecated GIO API
• Bump the dependency on GLib to 2.46
• Do not create `null` nodes for empty strings [#730803]
• Documentation fixes [Philip Withnall - #754384]
• Avoid crashes in the test suite [Iain Lane - #755977]
• Add simple iterator object for JSON objects [Philip Withnall - #755509]
• Detect missing commas in arrays
• Add support for g_auto* macros
• Allow making JSON types optionally immutable, in order to allow
  efficient hashing and equality tests [Philip Withnal - #756121]